To support a system bandwidth wider than LTE (Long Term Evolution) system, such as 100 MHz, one possibility is to directly distribute spectrum with bandwidth of 100 MHz for LTE-A (Long Term Evolution Advanced) system as shown in FIG. 1 and the other is the CA (Carrier Aggregation) technology, viz. aggregate some spectrums distributed to present system to form a larger bandwidth for LTE multi-carrier system; at this moment, uplink and downlink carriers in system can be configured asymmetrically, viz. a UE (User Equipment) may occupy number of N≧1 carriers for downlink transmission, and number of M≧1 carriers for uplink transmission, as shown in FIG. 2.
UCI (Uplink Control Information) comprises CQI (Channel Quality Indicator)/PMI (Precoding Matrix Indicator)/RI (Rank Indicator), ACK (Acknowledgement)/NACK (Negative Acknowledgement) and SR (scheduling request) information. In LTE Rel-8 (Release 8) system, UCI can be transmitted either on PUCCH (Physical Uplink Control Channel) or on PUSCH (Physical Uplink Shared Channel) by multiplexing with the data on PUSCH. Aperiodic CQI/PMI/RI information is transmitted only on PUSCH, which is triggered by 1 bit CQI request information in the UL grant (Uplink grant). If the 1 bit CQI request information with a value of “1” in the UL grant is detected, the UE shall generate the related aperiodic CQI/PMI/RI information according to the pre-configured feedback mode and transmit the corresponding aperiodic CQI/PMI/RI on PUSCH with multiplexing; otherwise, the UE will not transmitt the aperiodic CQI/PMI/RI information. Periodic CQI/PMI/RI information is transmitted on PUCCH according to the pre-configured reporting cycle if there is no PUSCH transmission in current subframe. ACK/NACK and/or SR information are also transmitted on PUCCH if there is no PUSCH transmission in current subframe. In case there is a PUSCH transmission in current subframe, all UCI (including CQI/PMFRI/ACK/NACK/SR if exist) shall be transmitted on the PUSCH with multiplexing.
Compatible with the LTE system, LTE-A system supports the transmission of UCI on PUCCH and/or PUSCH. At present, it has been agreed that LTE-A system can support 5 carriers at most for aggregation, viz. a UE may be scheduled with multiple PUSCH transmissions in one uplink subframe. In addition, it has been agreed that UCI can only be transmitted on one PUSCH in one uplink subframe in LTE-A system. Therefore, when UCI is transmitted through PUSCH while there are multiple PUSCH is scheduled for the UE in the same uplink subframe, it is necessary to determine which PUSCH is adopted for transmitting UCI.
During the implementation of the embodiments of the present invention, the applicant finds that the following problems at least exist in the available technology:
In LTE-A carrier aggregation system, multiple PUSCH transmissions may be available for a UE in one uplink subframe. When the UE intends to transmit UCI through PUSCH, there is still no specific solution on how to determine which PUSCH is adopted to transmit UCI.